Production of polycyclic hydrocarbons

ABSTRACT

POLYCYCLIC HYDROCARBONS ARE PRODUCED BY A THREE STAGE PROCESS IN WHICH A CYCLOPENTADIENE IS CONDENSED WITH AN ACYCLIC SUBSTITUTED OLEFINE, THE SUBSTITUENTS REMOVED FROM THE INTERMEDIATE TO FORM A DOUBLE BONE AND THE PRODUCT IN TURN REACTED WITH AN ACYCLIC CONJUGATED DI-OLEFINE. FOR EXAMPLE, VINYL CHLORIDE MAY BE REACTED WITH CYCLOPENTADIENE TO FORM NORTRICYCLYL CHLORIDE, THE LATTER DEHYDROHALOGENATED WITH A SODIUM ALCOHOLATE, AND THE NORBORNADIENE PRODUCED CONDENSED WITH ISOPRENE TO FORM 1,4ENDOMETHYLENE-6-METHYL-1,4,5,8,9,10-HEXAHYDRONAPHTHALENE. BY VARYING THE CYCLOPENTADIENE TO VINYL CHLORIDE RATIO IN THE FIRST STAGE POLYCYCLIC RING STRUCTURES CONTAINING AN INCREASING NUMBER OF RINGS MAY BE OBTAINED.

United States Patent Int. c1.c07c 13/28 US. Cl. 260-666 PY 14 ClaimsABSTRACT OF THE DISCLOSURE Polycyclic hydrocarbons are produced by athree stage process in which a cyclopentadiene is condensed with anacyclic substituted olefine, the substituents removed from theintermediate to form a double bond and the product in turn reacted withan acyclic conjugated di-olefine. For example, vinyl chloride may 'bereacted with cyclopentadiene to form nortricyclyl chloride, the latterdehydrohalogenated with a sodium alcoholate, and the norbornadieneproduced condensed with isoprene to form 11,4- endomethylene-6-methyl1,4,5,8,9,10 hexahydronaphthalene. By varying the cyclopentadiene tovinyl chloride ratio in the first stage polycyclic ring structurescontaining an increasing number of rings may he obtained.

The present invention relates to the production of polycyclichydrocarbons.

According to the invention a process for the production of polycyclichydrocarbons of general formula:

comprises (a) condensing a cyclopentadiene with an acyclic substitutedolefine of formula (b) removing XX from the intermediate so formed and,(c) condensing the product of (b) with an acyclic conjugated diolefineof structure In the above general formula n is zero or a whole numberpreferably a small whole number e.g. 1 to 3. n is most preferably zerohowever, the polycyclic hydrocarbon thereby being a naphthalenederivative.

X and X which may be the same or different are atoms or groups which,when linked to a carbon atom which is itself attached by a single bondto a carbon atom linked to a like atom or group, are capable of removalas XX to form a double bond between said carbon atoms. X and X may behydrogen or an ester group, particularly an ester derived from a loweral-kanoic acid containing up to six carbon atoms such as an acetategroup. If desired X and/or X may be converted to other groups morereadily removable e.g. an ester group may be converted to an alcohol inwhich case the XX removed may be HOH i.e. water. Preferably however Xand/ or X are halogen most preferably chlorine. In particular X may behydrogen and X halogen such as chlorine because we have found thathydrogen halide (XX') is most read- 3,641,173 Patented Feb. 8, 1972 iceily removed with minimum by-product formation. Removal of the hydrogenhalide may be achieved by means of a base, suitably an alkali metal oralkaline earth metal salt of an alcohol particularly a sodium orpotassium alkoxide such as tertJbutoxide, iso-octoxide or nonoxide. Ingeneral the isopropoxide or alkoxides containing 4 to 10 carbon atomsmay be used as may the alkoxides of dior trihydric alcohols containing asimilar number of carbon atoms. Removal of hydrogen halides by thealkali metal alkoxide is preferably carried out in the refluxing alcoholfrom which the alkoxide is derived or in a sealed system at atemperature of to 350 C. pref erably 180 to 250 C. e.g. 200 to 220 C.Suitably the concentration of the alkoxide in the alcohol is about onemolar. If desired solvents may also be present and a lower temperaturemay be used. For example in dimethyl sulphoxide the hydrogen halide maybe removed at a temperature in the range 50 to 100 C. It is preferred tomaintain the solution of the alkoxide as nearly anhydrous as possiblee.g. containing less than 1% by weight of water. It is also advantageousto remove the stage (b) product from the reaction zone as soon aspossible after its formation e.g. by distillation. This is particularlyrecommended if norbornadiene is the stage (b) product.

The residual valencies in the reactants in the process i.e. thecyclopentadiene, the acyclic substituted olefine and the acyclicconjugated diolefine may be satisfied by hydrogen or by hydrocarbon ornon-hydrocarbon substituents provided that these do not adversely affectthe reaction taking place. Suitable hydrocarbon substituents includealkyl groups, particularly lower alkyl groups containing up to sixcarbon atoms e.g. methyl or ethyl groups. Chlorine and bromine areexamples of non-hydrocarbon substituents. Cyclopentadiene itself (or inthe form of dicyclopentadiene) is a favoured reactant with a vinylderivative such as vinyl chloride to yield norbornenyl chloride which ondehydrochlorination yields norbornadiene. The preferred acyclicconjugated diolefine is isoprene because this leads to particularlyvaluable products particularly when condensed with norbornadiene. Otheracyclic conjugated diolefines such as butadiene, piperylene and2,3-dimethylbutadiene may also be used.

The product of stage (a) has the general formula:

and is produced by the reaction of the cyclopentadiene with the acyclicsubstituted olefine. This reaction may be conducted at elevatedtemperature and pressure e.g. temperatures in the range 0 to 300 C.preferably 100 to 250 C. most preferably to C. The pressure is usuallythe autogeneous pressure of the reactant at the temperature of thereaction e.g. up to 200 atmospheres. The value of n is determined by themolar proportion of cyclopentadiene to the acyclic substituted olefineused. Thus for n to be 0 the molar ratio of cyclopentadienev to olefineshould preferably be 0.121 to 1:1 more preferably 0.25:1 to 1:1particularly 0.25 :1 to 05:1 while for n to be 1 the ratio shouldpreferably be 1.75:1 to 2.25:1. The reaction time should preferably be0.5 to 3.0 hours more preferably 1.5 to 2.5 hours. If desired a solventmay be used for the reaction preferably an aprotic solvent e.g. diethylether, tetrahydrofuran, esters such as dinonylphthalate, aromatichydrocarbons such as benzene and xylene and cycloparaflins and parafiinssuch as cyclo' hexane and n-octane respectively.

3 The product after stage (b) has the general formula:

and is condensed with the acyclic conjugated diolefine preferably atelevated temperature and pressure. Temperatures in the range to 300 C.preferably 50 to 250 C. more preferably 170 to 210 C. e.g. 170 to 190 C.The pressure is generally the autogenous pressure of the reactants atthe temperature under consideration e.g. up to 200 atmospheresparticularly 1 to 100 atmospheres. Preferably the stage (b) product ispresent in excess more preferably in a proportion of 2 to 10particularly 2 to 5 mole stage (b) product to 1 mole acyclic conjugateddiolefine. In this stage it is preferred not to use a solvent, but ifone is used it should be an aprotic solvent.

If desired, mixtures of acyclic conjugated diolefines, e.g. isoprene and1,3-dimethylbutadiene, such asare obtained as a refinery distillationstream may be used to give a mixed product suitable as a comonomer.Alternatively a similar distillation stream e.g. containing hydrocarbonsof 4 to 8 carbon atoms, may be treated to remove all but one conjugateddiene and the mixture remaining comprising parafiins, mono-olefines,non-conjugated diolefines, acetylenes and the one conjugated diene maythen be used without further purification, the residual parafiins,non-conjugated diolefines, acetylenes and monoolefines not interferingwith the reaction. For example, such a concentrated refinery stream maycontain isoprene as the sole conjugated diene and be suitable for use inthe present process.

The products of the process are useful as termonomers inethylene/propylene/termonomer copolymers. For this purpose it ispreferred that one of the doubly bonded product was water washed andextracted three times with /60 petroleum ether. The extract was driedover sodium sulphate for 2 hours and then fractionally distilled torecover the norbornadiene produced. The yield of norbornadiene was 15.4grams.

146.2 parts of norbornadiene and 27.3 parts of isoprene (i.e. a molarproportion of norbornadienezisoprene of 4:1) were heated in a pressurevessel under a nitrogen atmosphere at C. for 15 hours. At the end of thereaction 167.0 parts of the contents of the reaction vessel weredistilled initially at atmospheric pressure to recover the unreactednorbornadiene which was suitable for recycle. Continuation of thedistillation produced a fraction boiling Within the range 82 C. to 102C. (mainly 101 C.) at 16 mm. pressure which was shown by analysis tocontain 93% of 1,4 endomethylene 6 methyl- 1,4,5,8,9,10hexahydronaphthalene (4 methyl-tricycle- [6,2,1,0 undecadiene-4,9

The following examples are illustrative of the individual stages of theprocess of the invention. Thus Example 2 illustrates stage (21), Example3 stage (b) and Examples 4 and 5 stage (c).

EXAMPLE 2 The apparatus consisted of a 1 litre autoclave fitted withcooling coils and heating mantle.

The autoclave was charged with a Weighed quantity of dicyclopentadienethrough a tundish and the vinyl chlo ride was added from a previouslycharged bomb. The autoclave and contents were then heated to therequired temperature and maintained there for the preset reaction time.

No samples were taken during the course of the reaction. At the end ofthe reaction time the autoclave was cooled to 40 C. and the excess vinylchloride flashed off, condensed in catchpots cooled in methanol andsolid dioxide, and weighed. The reaction product was egged out of thereactor, weighed and analysed by gas liquid chromatography. The resultsof a series of experiments under differing conditions are given in thefollowing table.

Yield,

Yield, Yield, Yield, NBC NBC plus NBC on NBC on plus NTC NTC on Time,Tempera- Mole ratio, VC, CPD, on V0, CPD Experiment hr. ture, O. VC/CPDpercent percent percent percent Norm-V0 =vinyl chloride (formed fromcarbon atoms in the cyclohexene ring is substituted by a lower alkylgroup such as a methyl group. A particularly useful product is1,4-endomethylene 6 methyl- 1,4,5,8,9,l0 hexahydronaphthalene which maybe produced from cyclopentadiene, vinyl chloride and isoprene by thepresent process.

The invention will now be further described with reference to thefollowing examples.

EXAMPLE chloride; CPD =cyclopentadiene; NBC=norbornenyl chloride; NTC=nortricyclyl NBC by lsomerisation).

EXAMPLE 3 Solutions of sodium hydroxide in the alcohols were prepared byheating sodium hydroxide pellets in the alcohol in a flask fitted with aDean and Stark head. The water of reaction was removed as an azeotropewith the alcohol and the water separated, the alcohol being run backinto the flask. Alternatively the sodium alkoxide was prepared bydissolving metallic sodium in the alcohols. Both methods of preparationproduced on approximately 1 molar solution of the sodium alkaoxide inthe alcohol.

The following results were obtained by reacting norbornenyl chloridewith the sodium alkoxides in sealed Carius tubes in a Carius oven. Thereaction products were analysed by gas-liquid chromatography fornorbornadiene and for norbornenyl chloride isomers and by Mohr titration(silver nitrate with potassium chromate indicator) for liberatedchloride ion, after neutralisation with nitric acid.

Yield N BD Tempera- Time, NBC on NBC Experiment Alkoxide ture, 0. hrs.converted converted a Sodium iso-octoxide 200 1 21. 6 100 b... Sodiumnonoxide 200 2 79. 3 76. 5 c-.- Sodium salt of phenyl 200 2 59. 4 100dimethyl carbinol. d. Sodium iso-octoxide... 200 2 77. 6 76. 9 e Sodiumiso-octoxide 240 5 79.0 47. 7

containing 2.4% water. Sodium iso-octoxide 240 5 92. 7 66. 2 containing0.6%

water. i. 2:: Sodium iso-octoxide 250 1 82.4 63. 9

l Alkoxide prepared from metallic sodium.

NorE.NBC=no1-borneny1 chloride, NBD =norbornadlene:

Original weight of NBC fina.l weight of NBC NBC converted x100 Originalweight of NBC Final weight of NBD Yield NBD on NBC converted=----- 100Weight of NBD if all NBC converted had formed NBD EXAMPLE 4 Theapparatus was a 5 litre autoclave constructed in The results of thevarious experiments are given in the following table.

Percent yield Conversion, EMHN based onpercent NBD: IP, Tempera- NBD IPmole ratio Time ture, C. NBD IF converted converted 4. 21 2 hrs., 7 mlns170 7. 47 55. 4 98.0 70. 4

5. 73 3 hrs., 10 mins 170 8. 95 72. 9 97. 78. 7

4. 44 3 hrs, 55 mins--- 170 17. 8 63. 96. 9 72.

4. 61 2 hrs., 57 mins.-. 180 11.0 85. 5 95. 8' 78.3

1. 03 3 hrs 180 35. 2 89. 2 85. 3 40. 4

2.02 3 hrs 190 30. 7 97. 8 89. 9 58. 2

8. 00 3 hrs..- 160 9. 5 66. 2 96. 4 65. 0

3. 3 hrs 200 26. 4 100. 0 92. 2 66. 0

Nora-NBD =norbornadiene, IP=isoprene.

chromium-stainless steel and fitted with an 18/8 /t1tan1um EXAMPLE 5internal cooling coil. The autoclave was also provided with a paddlestirrer. A separate vessel was produced, connected to the autoclave fromwhich isoprene could be delivered by means of an applied nitrogenpressure.

In operation, the required quantity of norbornadiene was charged to theautoclave and isoprene to the isoprene vessel and the autoclave heatedby means of electric heaters to the required temperature. When thetemperature was reached the electric heaters were cut out and theisoprene delivered to the autoclave'by means of the nitrogen pressure(11.5 bars). Complete isoprene addition was indicated by a sharp rise inthe autoclave pressure to the egging pressure of the nitrogen.

Although the autoclave temperature generally fell by -20 C. on additionof the isoprene it rapidly rose due to the heat of reaction. When theautoclave temperature was 3 C. above the desired reaction temperaturethe cooling water was turned on. Later during the reaction the coolingwater was dispensed with and the electric heaters used to maintain thereaction temperature.

After the reaction period the heaters were turned off and the coolingwater turned fully on. The autoclave was discharged with its contentswere at a temperature below C.

Samples of the reaction mixture were withdrawn from the autoclave duringthe reaction and both they and the final product were analysed bygas-liquid chromatography. The reaction product was also distilled torecover the 1,4- endomethylene-6-methyl l,4,5,8,9,l0hexahydronaphthalene (EMHN).

The apparatus and technique were the same as in Example 4. Instead ofessentially pure isoprene however an isoprene concentrate was used. Theisoprene concentrate was obtained from a steam cracked naphtha by firstseparating a C-S stream by distillation and then subsequently distillingthe C-S stream to give an isoprene concentrate and a piperyleneconcentrate. The C-S stream comprised hydrocarbons boiling in the range10 to C. and the second distillation was conducted to give a fractionboiling in the range 10 to 37 C. (isoprene concentrate) and a residue,the piperylene concentrate. The isoprene concentrate had the followingcomposition.

The results of three experiments conducted under different reactionconditions are given below.

7 We claim: 1. A process for the production of polycyclic hydrocarbonsof general formula in which n is zero or a whole number which comprisesin combination the following reaction steps:

(a) a cyclopentadiene is condensed with an acyclic substituted olefineof formula area 2. The process of claim 1 in which the residualvalencies in the cyclopentadiene, the acyclic-substituted olefine andthe acyclic conjugated diolefine are satisfied by hydrogen, by alkylgroups or by chlorine or bromine atoms.

3. The process of claim 1 in which X and/or X are hydrogen, an estergroup or a halogen atom.

4. The process of claim 3 in which X is hydrogen and X a halogen. I

5. The process of claim 2 in which the acyclic conjugated diolefine isbutadiene, isoprene, piperylene or 2,3- dimethylbutadiene.

6. The process of claim 1 in which the temperature in step (a) is in therange 100 to 250 C.

7. The process of claim 1 in which the ratio of the cyclopentadiene toacyclic substituted olefine instep (a) is 0.1:1 to 1:1.

8. The process of claim 4 in which XX is a hydrogen halide which isremoved in step (b) by means of a base.

9. The process of claim 8 in which the base is an alkali metal oralkaline earth metal salt of an alcohol.

10. The process of claim 8 in which the temperature is to 250 c. r

11. The process of claim 1 in which the temperature in step (c) is 50 to250 C.

12. The process of claim 1 in which the mole ratio of step (b) productto acyclic conjugated diolefine in the step (c) reaction is 2 to 10:1.

13. The process of claim 1 in which 1,4-endomethylene- 6methyl-1,4,5,8,9,10-hexahydro'naphthalene is produced by the followingcombination of reaction steps:

(a) cyclopentadiene is reacted with vinyl chloride for 0.5 to 3.0 hoursat a temperature of to C. and a ratio of cyclopentadiene to vinylchloride in the range 0.25:1 to 0.5:1,

(b) the norbornenyl chloride produced in step (a) in dehydrochlorinatedby reaction with sodium isopropoxide or the sodium salt of an alcoholcontaining 4 to 20 carbon atoms at a temperature of 180 to 250 C. and,

(c) the norbornadiene produced in stage (b) is condensed with isopreneat a temperature of 170 to 210 C. and mole ratio of norbornadiene toisoprene of 2 to 5:1.

14. The process of claim 13 in which the isoprene is contained in amixture of C to C hydrocarbons comprising parafiins, non-conjugateddiolefines, acetylenes and monoolefines derived from a refinerydistillation stream.

References Cited UNITED STATES PATENTS 3,565,962 2/1971 Walmsley 260666DELBERT E. GANTZ, Primary Examiner V. OKEEFE, Assistant Examiner US. Cl.X.R. 260648 C

